yes, lets be realistic. Automatically and transparently sharding across an arbitrary number of nodes is a case that is actually required by a tiny fraction of

yes, lets be realistic. Automatically and transparently sharding across an arbitrary number of nodes is a case that is actually required by a tiny fraction of the industry. And that fraction is already paying people to monitor and control that sharding because they're too large to trust the "automatic and transparent" algorithms. The big users of Cassandra and Hbase use them for deeper architectural reasons than simply automatic sharding.